How do I know what to check to prevent a breakdown?

You can fix what is broken. Someone hands you a failure and you set it right. What eludes you is the step before, knowing what to inspect so the failure never happens. That is a real gap, but a normal one. Repair teaches you what breaks. Prevention asks you to use that knowledge in reverse, and that reversal takes time to develop.\nStart from what you already know. You have seen many things fail. Each one had a cause, a worn part, a loose fitting, a buildup, a stress. Your prevention checklist is hiding inside your repair history. The parts you replace most often, the failures you see again and again, those are exactly the things worth checking before they go. You are not guessing from nothing. You are mining what your hands already learned.\nSo make it concrete. Write down the five or six most common failures you deal with. For each, note the early sign or the part that gives out. That list becomes your inspection routine, the things to look at on every job before there is a problem. Prevention is not a mysterious sense. It is your own experience, turned around and written down. Build that list this week and start checking against it.